Materials Literature
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We report the synthesis of solvent-stabilized lead-iodide nanoparticles, using a convenient route involving coordinating solvents. The resultant colloids show strong absorption features in the ultraviolet region of the optical spectrum, which are consistent with the formation of semiconducting nanocrystals of lead (II…
The detailed analysis of the 1H NMR hyperfine shifts according to the model-free methods shows that the semi-rigid monometallic complexes [Ln(L)(NO3)3] (Ln = Eu-Yb) are isostructural in solution. The associated separation of contact and pseudo-contact contributions to the hyperfine NMR shifts in each rhombic lanthanid…
Abstract Reactions of 2 equiv. pyrrole with [C 4 H 3 N(CH 2 NMe 2 )‐2] 2 M(NEt 2 ) 2 in toluene generated tetra‐pyrrolyl metal compounds [C 4 H 3 N(CH 2 NMe 2 )‐2] 2 M(C 4 H 4 N) 2 ( 3 , M = Zr; 4 , M = Hf) in moderate yields. Similarly, treatment of metal amides [C 4 H 3 N(CH 2 NMe 2 )‐2] 2 M(NEt 2 ) 2 with 2,6‐dimet…
We have designed and synthesized a HAB-based receptor with six ethereal oxygens on one face of the central benzene ring by a trimerization of a diarylacetylene in which the ethereal oxygens are tied together with a tetramethylene bridge. This unique amphiphilic receptor allows an efficient binding of a single potassiu…
Exceptional activity in carbon oxidation is displayed by a zeolite-supported ruthenium catalyst (see diagram; Y=carbon weight loss) that unlike platinum catalysts does not require the presence of NOx in the gas stream. This catalyst opens up a new route for catalytic soot oxidation in diesel engine exhaust filters.
This study investigates the effect of pretreatment of fiber with NaOH and coupling with maleated polypropylene (MAPP) on the physical and mechanical properties of composites, based on radiata pine (Pinus Radiata) fiber, produced with a polypropylene matrix, using a twin-screw extruder followed by injection molding. Pr…
Starting from a microscopic definition of an alignment vector proportional to the polarization, we discuss the hydrodynamics of polar liquid crystals with local C infinity v symmetry. The free energy for polar liquid crystals differs from that of nematic liquid crystals (D infinity h) in that it contains terms violati…
Polyphthalocyanines have potential application in the development of electronic materials. One-dimensional polyphthalocyanines are accessible through monomers having a trans-A2B2 structure, but the preparation of a truly linear polyphthalocyanine is challenging because of limitations imposed by the geometry of phthalo…
Reflectance spectrum calculations for a silicon oxynitride (SiOxNy)–porous silicon (PS) double layer antireflection coating is performed using the matrix method. The results are compared with the corresponding spectrum of diamond-like carbon (DLC)/PS and SiO2/TiO2 double layer coatings. A lower reflectance in the visi…
Copper hydroxyphosphate [Cu(2)(OH)PO(4)] with complex architectures has been synthesized through a simple and mild hydrothermal route in the absence of any external inorganic additives or organic structure-directing templates. Powder X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spect…
The codoping effect mechanism of Al and P on the solubility enhancement of Er(3+) ion in SiO(2) glass was clarified by electron spin-echo envelope modulation spectroscopy. It turned out that doped P ions preferentially coordinate to the Er(3+) ion to form a "solvation shell structure", and the environment is similar t…
The CPP (combined polymerization and pyrolysis) preparation route, in its enhanced liquid-precursor-based version, was combined with consecutive soft milling. For studies of temperature- and size-dependent structural changes occurring in ferroelectric lead titanate, this combined route yields a nanopowder series cover…
We report first-principles calculations of the structural, electronic and dynamical properties of the zinc-blende materials BP, BAs and BSb. The ground-state and electronic properties, i.e., the lattice constant, the bulk moduli and band structure, are calculated using a plane-wave pseudopotential method within the de…
Nanocomposites of poly(methyl acrylate) (PMA) with synthetic fluoromica (Somasif) as the inorganic component were studied as a function of clay content by the spin-label electron spin resonance (ESR) technique, X-ray diffraction (XRD), and differential scanning calorimetry (DSC). PMA was modified by attachment of nitr…
A high-pressure M\"ossbauer spectroscopy study of a spin crossover in $({\mathrm{Mg}}_{0.8}{\mathrm{Fe}}_{0.2})\mathrm{O}$ ferropericlase is presented. A low-spin subspectral component appears at about $55\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$, but there is a significant pressure region over which both high-spin and…
Ultrafine tungsten and tungsten oxide powders with controllable particle size and structure have been synthesized by a reverse microemulsion-mediated synthesis method. The nanoparticles were characterized by transmission electron microcopy, X-ray diffraction, and thermal analysis. Synthesis conditions, including water…
BaZr0.15Ti0.85O3 thin films were deposited on Pt-coated Si substrates using the pulsed excimer laser ablation technique. X-ray diffraction and atomic force microscope techniques were used to study the structural characteristics of the films. Films with good crystalline quality, with an average grain size of 0.5 µm wer…
The sticky spiral of araneoid spider orb webs consists of silk fibers coated with adhesive droplets. The droplets contain a variety of low-molecular-mass compounds (LMM). Within a species, a fairly consistent ratio of LMM is often observed, but substantial variability can exist. To gain insight into factors influencin…
During plastic flow of crystalline solids, dislocations self-organize in the form of patterns, with a wavelength that is inversely proportional to stress. After four decades of investigations, the origin of this property is still under discussion. We show that dislocation patterns verifying the principle of similitude…
Tunable Raman spectroscopy is used to measure the optical transition energies Eii of individual single wall carbon nanotubes. Eii is observed to shift down in energy by as much as 50 meV, from -160 to 300 degrees C, in contrast with previous measurements performed on nanotubes in alternate environments, which show ups…